UV Transmitting Glass Composition for Deep UV Transmittance and Weather Resistance
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Solution Overview
Problem
UV transmitting glasses with high transmittance in the deep UV region suffer from reduced weather resistance, leading to shorter product life in electronic devices.
Innovation Solution
A UV transmitting glass composition with specific ranges of SiO2, Al2O3, B2O3, and other oxides, optimized for high transmittance and weather resistance, including a highly accelerated stress test and glass viscosity characteristics, to maintain performance while enhancing durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a boron oxide-rich glass composition is used to enhance UV transmittance, then the transmittance in the deep UV region is improved, but the weather resistance is lowered
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of multiple glass components. Specifically, it limits B2O3 to 10-30 mass%, SiO2 to 60-78 mass%, and Al2O3 to 1-25 mass%, while also controlling alkali metal oxide contents (Li2O <1.9%, Na2O <8%, K2O 1.6-8%). This multi-parameter optimization resolves the contradiction by finding the optimal balance point where UV transmittance is maximized while weather resistance is maintained through controlled alkali content and appropriate SiO2-Al2O3-B2O3 ratios.
Solution Approach 2:
The patent employs composite material principles by creating a multi-component glass system that combines SiO2, B2O3, Al2O3, and controlled amounts of alkali metal oxides. This composite approach allows the glass to exhibit both high UV transmittance (from the B2O3-SiO2- Al2O3 network) and good weather resistance (from controlled alkali content and network formers), resolving the trade-off between these two properties that cannot be achieved with single-component or simple compositions.
2Illumination intensity
If the transmittance of UV transmitting glass in the deep UV region is increased, then the performance of light source is improved, but the product life of electronic device is shortened
Solution Approach 1:
The patent resolves this contradiction through parameter changes by optimizing the glass composition to achieve external transmittance of 40% or more at 200 nm while simultaneously ensuring high weather resistance. The specific composition ranges (B2O3: 10-30%, SiO2: 60-78%, Al2O3: 1-25%, with controlled alkali metals) create a glass that maintains both superior UV transmission for light source performance and enhanced durability for extended product life, eliminating the trade-off present in conventional glasses.
Data Source
AI summary
A UV transmitting glass of the present invention is characterized by including as a glass composition, in terms of mass %, 60% to 78% of SiO2, 1% to 25% of Al2O3, 10.8% to 30% of B2O3, 0% to less than 1.9% of Li2O, 0% to 8% of Na2O, 1.6% to 8% of K2O, 1.6% to 10% of Li2O+Na2O+K2O, 0% to less than 1.9% of BaO, 0% to less than 1.9% of Li2O+BaO, and 0% to 1% of Cl, and having an external transmittance at a thickness of 0.5 mm and a wavelength of 200 nm of 40% or more.